I borrowed from a friend the LEGO blocks and men mold's that she purchased from LEGO Land in San Diego on vacation. However, you can also purchase the molds online from several different sites. I believe they are called "ice cube molds"
I made this Double Decker Lego Cake for my son's 6th birthday, he loves Lego and I knew he would love this cake!
The top cake: Banana with a homemade butter cream frosting. I just tinted it blue to brighten it up. It is made with 1 traditional 9" cake pan, after it cooled I froze it for 30 mins, sliced it in half long ways so I had two pieces. Freezing it makes it much easier to frost with less "cake" in your frosting.
The bottom cake: Chocolate Sour Cream cake, starting with a box cake then adding 1 cup sour cream, 1/2 water. 1/2 oil & 4 eggs. I baked this cake in a larger spring foil pan and lined it with parchment paper. It came out beautiful and didn't stick. After it cooled I also put it in the freezer then sliced it to make 2 portions. I frosted it with homemade chocolate butter cream.
First I frosted the bottom cake, chocolate in the middle and then I frosted the entire top and sides. I then decorated it with the homemade Lego shapes (how to make below). I then frosted the top cake, banana, on a dinner plate upside down so I could easily remove it and place it on top of the chocolate one once it was ready. It was actually pretty easy to place on top of the chocolate one since it was still partially frozen. I then decorated the sides and top of the cake with the Lego shapes.
To make the Lego shapes, purchase the wafer size meltable chocolate, white chocolate or colored ones, melt in the microwave and fill the molds. After about 30 mins, I put the molds in the fridge for about 15-20mins as I found it was easier to pop them out without breaking the men's heads or arms. You will want to start this process 2-4 days before you actually make the cake. Store the shapes at room temp. on parchment paper in a loose fitting container.